There's got to be some give and take in a relationship with an employer. If you're feeling exploited, you're not in the right role. And that will show in the quality of your work. Work can be fun and interesting, and someone who enjoys what they do will relish the opportunity to learn. I know that for me interviewing, though tough, has always been an opportunity to solidify my basic understanding of the field I'm in. Maybe figure out what you enjoy, and find an employer who respects you equally?